I can relate to having a weak bench. I've been trying to push mine up for the last year, and I just got back to where I used to be in high school (still a meager 120# one-rep max).
Couple quick tips:
-Don't work the bench every day. It's tempting, but you build more muscle healing and resting than actually lifting. 2-3 times per week should be adequate.
-Working isolate muscles individually, like triceps and chest, has little carry-over to the bench. Shoulder work does help some since it improves the stability of the joint, making benching way less painful.
-Balance pushing movements with pulling, i.e., benching with rowing, overhead pressing with pull-ups, etc. Your joints will thank you.
I'm thinking of putting together a bench program in couple weeks. I'll post it here if it works out for me.
1) eat real food - more vegetables, moderate meat, moderate fruits, less grains, less sugar, less vegetable oils.
2) exercise - moderate intensity cardio, sprinting, heavy lifting, dedicated stretching and mobility.
3) live - relax, de-stress, meditate.
Disclaimer: I'm not professionally qualified to make any formal recommendations. I've just done my homework and I'm my own guinea pig. All of my data, unless otherwise cited, comes from a sample size of n=1 (me).